Books



1959 E. A. WHITEFORD ETAL 2, 6,

BOOKS Filed Nov. 23, 1956 INVE T R. Q. z/l ai By QAZZ'MM ATTORNEYS for long periods of time.

United States Patent Ofiice 2,916,304 Patented Dec. 8, 1959 BOOKS Errington A. Whiteford, New York, N.Y., and Faber Birren, Stamford, Conn., assignors to Whiteford Paper Company, Inc., New York, N.Y., a corporation of New York Application November 23, 1956, Serial No. 624,117

2 Claims. (Cl. 28363) This invention relates to books and pertains particularly to book papers and printing inks used therein.

It is an object of the invention to provide a book in which the character of the book paper used in the leaves thereof, and the character of the printing inks used thereon are coordinated to improve the efliciency, comfort and pleasure in the task of reading.

Other objects and advantages of the invention will appear hereinafter.

A preferred embodiment of the invention selected for purposes of illustration is shown in the accompanying drawing, in which the single figure is a perspective view uf a book.

A great amount of technical research has been conducted during recent years on visibilty and legibility as related to reading comfort. It is obvious that extreme contrast, such as black ink on white paper, offers maximum stimulation to the eye. Yet the solution of the problem of reading comfort by no means rests with this obvious fact alone.

The whole matter of seeing and reading is complex. It is largely related to sensation, to images which are formed on the retina of the eye by light energy and transmitted to the human brain. It goes without saying that the brighter the image the more noticeable it is. The same applies to extreme contrasts; i.e. black on white. Yet even here, the intensity of the stimulation has its limit of useful effect. Strong light sources create glare, cause vague images and may be physically uncomfortable. In a similar way, white paper, printed with black ink, and read under strong natural or artificial light, may not only cause distress through glare, but images or type matter so perceived may actually appear blurred and diflicult to read. Seeing efliciency is at its most comfortable best where illumination is not unduly intense, where the surface in view is relatively diffuse or set where it is free of specular reflections, and where the contrast between paper and printed matter does not intrude an excessive range of brightness difference.

Most persons today read printed matter, notably books, under illumination (foot-candle) levels that are many times greater than in the past. Adequate illumination has been achieved through advancements in the lighting industry and is to be found everywhere in homes, schools, ofiices, etc. The need for excessive contrast has thereby been lessened. Moreover, where strong contrast is viewed under strong light, visual fatigue may be heightened and seeing itself impaired.

It must be recognized that in reading books, the attention of the reader is usually fixed and concentrated The need for high stimulation, such as might be required in viewing a traffic sign or poster, is wholly secondary. With attention directed to printed pages, and with the eye exposed to them over long periods of time, far greater comfort is assured Where the nerves of the eye are not overexcited by excessive brightness or by strong contrasts.

To illustrate, there is no visibility or legibility advantage to black printing on white paper over other and less extreme contrasts where the size of the characters, letters or words seen is reasonably large in size, such as 12 point type read 14 inches from the eye. Where the images seen are easily accommodated and focussed, virtually any contrast ratio above 2 to 1 is adequate. The high contrast ratios of black printing on white paper of about 17 to 1 are excessive and unnecessary.

There are good reasons for this. First of all, strong contrasts are likely to produce marked after-images which may persist for several seconds. If the eye remains stationary for a short period, ghost images may be thrown in conflict with actual images and the clarity of the printed page may then be confused.

Secondly, great brightness, such as received from white paper viewed under strong light, will tend to over stimulate the retina of the eye. Because the excitation of brightness on the nerves of the eye acts generally like water on blotting paper, the bright area may overlap and fog the dark area, with the result that the images, instead of being distinct and clear, will be blurred.

Thirdly, excessive contrast and brightness are fatiguing and psychologically as well as visually uncomfortable. Such sharpness is just as irritating to the eye as sharp sounds, tastes, odors and temperatures are distressing to the other senses.

According to the present invention, we propose to reduce this excessive contrast and brightness, by properly coordinating the characteristics of the paper and printing ink used thereon. For this purpose, we reduce the reflectance of the paper and therefore its brightness and glare, and at the same time we increase the reflectance of the printing ink used thereon to reduce the contrast between paper and ink.

In the drawings, the invention is illustrated as embodied in a book 1 of ordinary construction comprising leaves 2 and cover 3. The leaves may be bound in any suitable manner. The book leaves are printed in the usual manner, but the printing 4 is done with printing inks as hereinafter described.

According to the present invention, we propose to tint the paper of which the book leaves 2 are made. The tinting may be in any color which is deemed to produce the desired psychological response. Such tinting has the desired effect of reducing the reflectance and therefore glare of such paper below that of white paper of similar quality and texture. The amount of coloring matter added to the paper is adjusted to produce tints which will reflect a maximum of and a minimum of 70% of the incident light, with 75% being the most desirable for most purposes. White paper reflects about of the incident light, and reduction to the levels set forth is found to lessen retinal stimulation, blurred images and visual discomfort.

In addition to reduction of reflectance and glare, color itself offers important advantages for book paper. Reading demands mental attention as well as visual distinction. There is a difference between mere ability to read (legibility) and desire or pleasure in reading. Whereas, white and black are more or less emotionally negative, tinted colors are attractive, compelling and intrigue interest. In eye-fixation tests of small children, colors draw more attention and hold attention for longer periods than neutral tones. Within the above limits of reflectance, the particular hue may be selected on the basis of emotional preference. Preferably the hues are selected from the primary areas of color vision such as reds, yellows, greens and blues, because these embody the simplest of visual and psychological response, and are recognized as primary in the scientific field.

Preferably such book paper is provided with a dull matte finish which produces a diffuse reflection and assures a soft and uniform distribution of illumination from all angles.

Further, for printing on such tinted paper, we propose to use colored printing inks having increased reflectance as compared with black inks. That is, whereas black inks reflect about 5% of incident light, We propose to use colored inks which reflect a minimum of 8% and a maximum of 12% of the incident light, with being the most desirable for most purposes.

However, as an additional and most important aspect of the invention, we correlate the reflectance of the paper with the reflectance of the ink used for printing thereon to obtain a contrast ratio not greater than 10 to 1, not less than 7 to 1 and preferably of about 8 to 1 for optimum reading results.

By contrast ratio, as used herein, we mean the ratio of reflectance of paper to reflectance of ink used for printing thereon. Thus, for White paper having a reflectance of 85% and black ink having a reflectance of 5%, the contrast ratio is 17 to 1 which after careful research has been judged to be needless and excessive for comfortable reading. According to the present invention, using a tinted paper having a reflectance of 75% and a colored ink having a reflectance of 10%, a contrast ratio of 7.5 to 1 results.

Further, according to the present invention, we propose to use a printing ink of a color which is chromatical- 1y related to the tint of the paper on which it is printed. Thus, if the paper is tinted with red to produce a pink tint, for example, a dark red ink, such as a maroon would be used. If the paper is tinted blue, a dark blue ink would be used. If the paper is tinted green, a dark green ink would be used, and if tinted yellow, a dark yellow ink would be used. Such correlation of color avoids hue conflict and presents a pleasing and harmonious combination.

It will be understood that the invention may be variously modified and embodied within the scope of the subjoined claims.

We claim as our invention:

1. A book having leaves made of paper, having coloring matter therein sufficient to produce a tint which reflects a maximum of 80 percent and a minimum of percent of the incident light, said leaves being printed with a colored ink which reflects a minimum of 8 per cent and a maximum of 12 percent of the incident light and which comprises the same hue as the coloring matter tinting the paper.

2. A book as claimed in claim 1 in which the contrast ratio between said paper and ink is not greater than 10 to 1 and not less than 7 to 1.

References Cited in the file of this patent UNITED STATES PATENTS 1,365,935 Moran Jan. 18, 1921 1,481,529 Baltz et al. Jan. 22, 1924 1,659,734 Hurley Feb. 21, 1928 1,659,952 Hurley Feb. 21, 1928 

